Use retention policies to automatically archive messages

Outlook for Mac has never had an automatic archiving feature. And it still doesn’t. However, Outlook 15 supports accessing Online Archive messages stored on Exchange 2010 or higher and Office 365 servers. These servers use a feature called retention policies, which automatically archive messages based on schedules set by the administrator.

The advantage retention policies offer is they run on the server and don’t require Outlook to move messages. An administrator can create multiple retention tags within a policy allowing the end-user to choose which he’d like to apply to individual folders. For example, an end-user can apply an “Archive After 10 Days” tag to a high traffic mail folder.

InboxWhy archive?

Email use has been mainstream for nearly two decades but many end-users still find managing the amount of email they send and receive tedious. Few ever plan beforehand how they’ll manage the thousands of messages received each year. And after receiving thousands of messages, few want to deal with filing or deleting them.

So, messages pile up. The Inbox soon has several thousand messages accumulated over years. Attempts at filing away messages by sender or date are abandoned.

After months or years of neglected management, Outlook slows down or is constantly syncing and never catches up. One day it stops altogether or the database gets corrupt and needs repairing. Repairing takes hours or days because of the sheer volume of messages that need examining.

Archiving solves a few problems:

      • It moves old messages out of the way of current messages, making the Inbox easier to browse.
      • It keeps the Inbox (the folder most synchronized with the mail server) from growing obese, which can slow or stop mail flow altogether.
      • It makes searching (Spotlight) for current messages faster and easier by moving old messages to a location that’s not searched. Finding a needle in a small haystack is easier than finding it in a huge one.
      • It makes searching archived messages faster because the burden is put on the server to find them rather than the Mac.
      • It allows keeping old messages for historical purposes but keeps them out of the way of day-to-day work.

Create a retention tag

Only an Exchange administrator or a company administrator for Office 365 can create or edit a retention policy. Microsoft pre-populates an organization’s retention policies list with a Default MRM Policy containing 13 retention tags. Those tags include:

1 Month Delete
1 Week Delete
1 Year Delete
5 Year Delete
6 Month Delete
Default 2 year move to archive
Deleted Items
Junk Email
Never Delete
Personal 1 year move to archive
Personal 5 year move to archive
Personal never move to archive
Recoverable Items 14 days move to archive

The Default MRM Policy applies to every mailbox unless the administrator decides to create his own policy with a different set of retention tags.

        1. Log in to the Exchange Admin Center at
        2. Choose Compliance Management > Retention Tags.
        3. Click the + menu button and choose Applied By Users To Items And Folders (Personal). This creates the new tag without applying it to any account or folder.
          New retention tag
        4. In the New Tag Applied By Users To Items And Folders (Personal) window, complete the following information to create a retention tag for archiving messages 10 days and older.
          Name — Archive After 10 Days
          Retention Action — Move to Archive
          Retention Period — When the Item Reaches The Following Age (In Days): 10
          Comment — Moves items 10 days and older to similarly named folder in Archives.
          New retention tag settings
        5. Click the Save button.

Add a retention tag to a retention policy

Remember, a retention tag is just a schedule. The newly created retention tag hasn’t been applied to any user mailboxes yet. The administrator must next add the retention tag to a retention policy (a group of retention tags with different settings), which he then applies to user mailboxes.

  1. Return to the Exchange Admin Center at
  2. Choose Compliance Management > Retention Policies.
  3. Double-click the Default MRM Policy to edit it. Or click the + symbol to create a new retention policy.
    Default MRM Policy
  4. Click the + symbol to open the Select Retention Tags window.
  5. Choose the newly created Archive After 10 Days retention tag and then click the Add button.
    Add retention tag
  6. Click the OK button to close the Select Retention Tags window.
  7. Click the Save button to close the Default MRM Policy window.

Add a policy to an account

The administrator’s work is complete. He has created a retention tag (a schedule) and added the retention tag to a retention policy (a list of schedules). This makes is available to the end-user to add to his own list of retention policies.

  1. The user now logs in to the Exchange or Office 365 account at without the “ecp”.
  2. Choose Settings (cog icon) > Options.
  3. Choose Retention Policies from the list on the left. Note the list of retention tags does not yet contain the new Archive After 10 Days tag.
  4. Click the + symbol to view the Select A Policy window.
  5. Choose the new Archive After 10 Days policy and click the Add button.
    Select A Policy
  6. Click the Save button to close the Select A Policy window.

Apply the policy to a mail folder

Finally, the end-user applies the retention tag to one or more folders of his choosing.

  1. Log in to the Exchange or Office 365 account at without the “ecp”.
  2. In the folder list on the left, click the More link to show all folders.
  3. Right-click or Control-click a folder and choose Assign Policy > Archive After 10 Days.
    Assign policy

Now what?

Messages won’t move immediately. By default, the retention policy process only runs once per week. That means messages may not move to the Online Archive folder for up to seven days.

When messages move to the Online Archive, they’ll appear in Outlook 15  in the same folder hierarchy under “Online Archive – name of account”.

Online Archive

The contents of this folder are never synchronized to Outlook and never consume space on your Mac. These messages are completely online (in the cloud) until you select one. It’s then downloaded and displayed. It stays downloaded and available until Outlook restarts. Then the local copy of the message is deleted.

This also means your Mac must be connected to the Internet to access your archived messages. If you need to refer to some messages offline, drag them to a mail folder under On My Computer. Don’t defeat the purpose of the online archive by dragging all your messages to On My Computer!

Online Archive folders are also not searchable unless you specifically select an archived folder. Searching Outlook using the All Mailboxes option warns Outlook will not search online archives.

Outlook will not search your online archives

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4 comments to Use retention policies to automatically archive messages

  • Cameron

    This was an excellent post. Thank you very much for the detailed info!

  • Cyrus

    Bill – will OL 2016 for Mac have the option to apply policies using the client or will users have to resort to OWA?

    • I’m sure Outlook for Mac will eventually allow users to apply archive policies like Outlook for Windows can do. When? I have no idea. For now, OWA is the only option.

  • GiuseppeA

    Thanks a lot. Your post is amazingly clear.
    You should be writing how to’s instead of Microsoft.
    Your support on the forum as well is highly appreciated.